Patients suffering from diseases like diabetes have to frequently self-administer injections. Medicament delivery devices like pen injectors, auto-injectors and safety syringes have been developed to facilitate self-administering injections. Typically, such delivery devices contain a predetermined amount of medicament and are discarded after use or contain replaceable cartridges of medicament. The delivery devices are re-usable and refitted with sterile injection needle assemblies to minimize the risk of infections.
A conventional needle assembly is screwed onto the delivery by a threaded connection. However, users are unaware of a proper amount of torque to secure the needle assembly to the delivery device, and as a result, typically over-tighten the needle assembly. Over-tightening can result injury (e.g., needlestick) while attaching or removing the needle assembly to/from the delivery device. Also, over-tightening may structurally impair the delivery device. Thus, there is a need for a needle assembly system which induces the use of the proper amount of torque to engage the needle assembly and the delivery device.